Limit key repeat of carriage return to one focused text input client

This CL introduces a kind of transaction mechanism where
"carriage return" generated by key repeat does not continue once
focused text input client is changed to one from another.

The problem reported in issue 319100 is that holding enter key
generates repeated "carriage return" character events even after
the focused text input client is changed from OmniBox to 
RenderWidgetHostViewAura.

With this CL, such repeated "carriage return" events will be
silently drained in the IME layer (ui::InputMethodWin) so that each
text input client will not be bothered.

Note: This CL is expected to be cherry-picked to M-32 branch.

BUG=319100
TEST=manually done on Windows 8.1

Review URL: https://codereview.chromium.org/64453005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236194 0039d316-1c4b-4281-b951-d872f2087c98
Adding nhiroki to some fileapi directory owners

BUG=none
R=tzik
NOTRY=true

Review URL: https://codereview.chromium.org/77073003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236195 0039d316-1c4b-4281-b951-d872f2087c98
Blink roll 162317:162330

http://build.chromium.org/f/chromium/perf/dashboard/ui/changelog_blink.html?url=/trunk&range=162318:162330&mode=html
TBR=
BUG=

Review URL: https://codereview.chromium.org/77193003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236196 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236195
Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236197 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236197